Donor apparatus and method

ABSTRACT

A developing system for latent images wherein a rotating fur brush receives marking particles from a donor assembly comprising a plurality of discrete elongated donor members which are successively moved through a closed path defining a volume within a sump housing, a portion of the defined volume being occupied by marking particles contained in the housing. The donor members may be circular, crescentic, or other configurational cross-sections and may or may not cooperate with a doctor blade. They may be in the form of taut flexible elements which are vibrated slightly to remove excessive toner. In certain embodiments, a striking element in the form of a thin taut but flexible wire or other material is used to charge and fluff the fibrous applicator as well as redistribute undesirable concentrations of toner within the applicator.

United States Patent 1151 3,687,106

Stange 1 Aug. 29, 1972 DONOR APPARATUS AND METHOD FOREIGN PATENTS ORAPPLICATIONS Inventor: Klaus g Pittsford, N 976,998 12/1964 GreatBritain ..118/637 [73] Asslgneez Xerox Corporation, Rochester, NY.Primary Examiner Mervin Stein [22] Filed: Sept. 24, 1969 Att0meyJa1nesJ. Ralabate, John E. Beck and 21 Appl. No.1 864,265 Benlamm SklarRelated U.S. Application Data [5 7] ABSTRACT [63] Continuatiomin' art ofSer No 840 967 Jul A developing system for latent images wherein arotat- 11 1969 b d y ing fur brush receives marking particles from adonor a an one assembly comprising a plurality of discrete elongateddonor members which are successively moved through [52] US. Cl...118/621, 117/ 17.5, 118/637 a closed path defining a volume within aSump hous [51] Iltt. Cl. ..G03g 13/08 ing, a portion of the define-dvolPme being QccuPied 0f ..1 conta ned n the hous ng 1l8/ donor membersmay be circular, crescentic, or other configurational cross-sections andmay or may not [56] References Cited cooperate with a doctor blade. Theymay be in the form of taut flexible elements which are vibrated UNITEDSTATES PATENTS slightly to remove excessive toner. In certain embodi- 3003 462 10/1961 Streich Sr. ..117/17.5 x men, a striking element in thea thin 5 X flexible Wirfi or other material is used to Charge and3283703 11 966 118 /63'7 X fluff the fibrous applicator as well asredistribute un- 2822779 M1958 Schroeder "117/17 5 X desirableconcentrations of toner within the applica- 3,532,071 10/1970 McCarroll..118/637 3,357,403 12/1967 Donalies ..118/637 16 Claims, 10 Drawingfigures P'A'TE'NTEDAUBZQ 1912 saw 1 or A F/GZ INVENTOR.

KLAUS K. STANGE ATTORNEY PATENTHlwszs I972 SHEET 2 OF 4 F/IG. 4

DONOR APPARATUS AND METHOD This is a continuation-in-part of applicationSer. No. 840,967 filed July ll, i969, now abandoned, assigned to thesame assignee as the instant application.

This invention relates generally to donor assemblies, for making markingparticles available to a developing applicator in apparatus wherein alatent image, either electrostatic or magnetic, is to be developed withsuch particles.

In conventional developing systems, a rotating cylindrical natural furbrush has sometimes been used to convey marking particles, or toner,into transfer relation with a latent image to be developed.

In the past, toner has been sprinkled or blown onto the brush, as wellas brought into contact with the brush via a donor assembly in the formof a solid cylindrical roller which rotates in a sump of developer,i.e., toner and carrier bead mixture.

However, these approaches have suffered severe limitations anddisadvantages which directly affect the quality and consistency of thedevelopment of latent images.

One disadvantage is the effect of pumping or the uniform and constantmovement of the developer in one direction as the roller moves throughthe sump. As the body of the roller moves it pushes developer before itand soon forms a cavity in the quantity of developer in the sump.Additionally, when prior art systems were inactive for long periods orin storage the developer mixture would cake and compact thereby makinggood development impossible without stirring the mixture prior tooperation. Such conditions were alleviated by additional apparatus suchas complicated vibrators or agitators which attempt to cause thedeveloper to break up or fall into this cavity to the extent that thedonor assembly will allow. While augmenting the total cost complexityand size of the development system, these remedies are partial at bestin their success.

Another solution is to use a large amount of carrier beads in thedeveloper mixture to lend more fluidity to the toner or pigmentedmarking particles. In this way, the developer mixture will more readilyseek its own level in the sump. However, such large concentrations ofcarrier beads consume precious space in the developer assembly whichcould better be occupied by toner thereby shortening the intervalbetween service calls or operator intervention to replenish the tonersupply.

Many times such prior art apparatus cannot present to the donor assemblya constant amount of developer since this amount is a function of thevarying level of developer in the sump. Furthermore, in many instances acertain residual amount of developer remains unused in the sump since itcannot be placed within the effective reach of the donor assembly.

The prior art use of natural or synthetic fibrous applicators fordeveloping latent electrostatic charge patterns in conjunction with asolid cylindrical donor roller encounters additional difficulties. Thecontact between the applicator and the recording surface to be developedas well as the contact with the donor roller have the undesirable effectof compacting the fibers of the applicator. This results in adegradation of the developed image. To restore the fluff of theapplicator to a degree required for good development, a striker plate orcomb structure has been suggested by the prior art such as U.S. Pat. No.3,251,706 to L. E. Walkup. However, these structures are believed tohave drawbacks such as complex mounting arrangements and excessive tonerbuildup on the structure itself.

In addition, to the disadvantages and limitations enounced above, priorart donor systems also employ a donor assembly which consumes valuablespace within the volume defined by the sump thereby reducing thecapacity thereof.

In prior art donor assemblies, doctor blades are required to insure thatonly a very uniform and predetermined amount of toner is carriedby thedonor roller or element to the developing brush. Besides the obviousdrawback of cost, such doctor blades, once damaged or nicked, would failin achieving uniformity of toner on the donor roller and hence createinconsistencies in the developed images. Damage could be the result ofcarrier beads or brush bristles being carried up by the donor roller orother contaminants getting into the system. These foreign elements inthe donor assembly threatened not only to damage the doctor blade butalso, more seriously, to damage the surface of the donor roller. Thislatter damage may extend along the entire circumference of the rollercausing the applicator to have an excessive concentration of toner in awell defined area resulting in a consistent contrast deviation in thedeveloped image. The cure for such a problem is replacement of the donorroller. 7

In mobile or unstable environments, the disorientation of the developerassembly causes undesirable shifts of developer in the donor assemblymaking uniform developing difficult since the developer may only be atone end of the donor assembly.

Also, certain solid types of donor assemblies also render the reloadingof the sump difficult unless total accessibility to the sump ispermitted.

It is, therefore, an object of the present invention to improve donorassemblies for toner conveyance to a developing member.

It is also an object of the present invention to provide improved donorassemblies which are efficient independent of additional apparatus forresituating developer in the sump.

Another object of the present invention is to provide an improved donorsystem wherein the effective capacity of the sump is maximized withoutaltering the size thereof.

Yet another object of the present invention is to provide an improveddonor assembly which can operate efficiently without carrier beads ordoctor blades.

And a further object of the present invention is to provide an improveddonor assembly which is insensitive to disorientation.

Another object of the present invention is to provide improved fibrousapplicator developing systems wherein the donor assembly maintains thefibers of the applicator in a condition conducive to good development.

It is an object of the present invention to also provide an improvedstriking member which efficiently fluffs a fibrous developmentapplicator as well as uniformly distributes toner among the applicatorsfibers.

A still further object of the present invention is to provide a donorassembly which permits easy replenishment of the sump.

These and other objects which may become apparent are accomplished inaccordance with the principles of the present invention wherein thedonor assembly is comprised of a plurality of elongated members whichdefine a volume at least partially occupying a sump of marking materialthrough which these members are moved during operation. The donormembers may be circular, crescentic, or other configurationalcross-sections and may or may not cooperate with a doctor blade. Theymay be in the form of taut flexible elements which are vibrated slightlyto remove excessive toner. In certain embodiments, a striking element inthe form of a thin taut but flexible wire or other material is used tocharge and fluff the fibrous applicator as well as redistributeundesirable concentrations of toner within the applicator.

These objects and other features of the present invention may beappreciated and better understood upon reading the following detaileddescription in connection with the appended drawings wherein:

FIG. l is a cross-sectional view of one embodiment of the presentinvention showing the sump housing, donor and developing assemblies;

FIG. 2 is a cross-sectional view of an alternative embodiment of thepresent invention showing a detachable sump;

FIG. 3 is a cross-sectional view of another alternative embodiment ofthe donor assembly of the present invention;

FIG. 4 is a cross-sectional view of an alternative embodiment of thedonor assembly.

FIG. 5 is a cross-sectional side view of another embodiment of thepresent invention showing the sump housing and donor assembly;

FIG. n is a cross-sectional view of one of the donor wires used in theembodiment of FIG. 5;

FIG. 7 is a front view of the embodiment of FIG. 5 with some partsbroken away for clarity;

FIG. 8 is an illustration of a portion of another embodiment of a donorassembly of the present invention showing a vibrator different from thatshown in FIG. 5;

FIG. 9 is an alternative embodiment of the donor assembly usingnon-parallel donor members; and,

FIG. lltl is an alternative embodiment of the present inventionemploying a striking element in accordance with the principles of thepresent invention.

Reference will now be made to FIG. II which illustrates in cross-sectionan embodiment of the present invention in the environment of anelectrographic recorder. As is well known, in electrography discreteelectrostatic charge patterns are placed on an insulative recordingmedium which are then rendered visible through appropriate developingtechniques. Basically, any developing technique consists in bringingsuitable marking particles into contact or close proximity with thelatent pattern to be developed. These particles are then attracted andheld by the pattern making it visible.

FIG. 11 illustrates one such developing technique in the form of acylindrical applicator, such as natural fur brush 2, which is mountedfor rotation about shaft 4. A support member 6 is spaced from shaft 4 sothat as the brush rotates in the direction of the arrow a latentpattern-bearing recording medium '7 supported by member 6 will partiallyobstruct the bristles at that portion of the brush 2 adjacent thereto.

The developing brush 2 is isolated from the remaining areas of theapparatus in which it is incorporated by way of a shroud or housing fland a silicon rubber seal 10. The former may be supported by the machineside frame while the latter is supported along one edge of the sumphousing designated by the reference numeral 12. The other edge of thesump housing has attached thereto a movable door M which is hinged tomove about a shaft 16. Through this opened door I l, developer materialmay be loaded into the sump housing 12.

Within the sump housing is a donor assembly comprised essentially offour components. A basic shaft 18 is power driven to rotate the donorassembly in a direction indicated by the arrow and this shaft may besuitably fixed for rotation to a side frame of the apparatus in whichthe present invention is incorporated. It should be understood that thisshaft 118 would then pass through one side panel of the sump housing 12.

Fixed to this shaft for rotation therewith is a flange member 2d whichis positioned in and to one side of the sump housing. This flange member2@ has two support flanges 22 and 2 associated with it which extendtherefrom in a direction substantially parallel to the axis of shaft118. It may be apparent that support flanges 22 and 24 may be integralwith flange member 20 such that components 20, 22 and 2d are actuallyone piece of material.

Attached to the outer surface of support flanges 22 and 241 or thesurface remote from shaft 18 are two arcuate or crescentic members 26and 28, respectively. Each of the elements 26 and 28 which will bereferred to hereinafter as donor members have two edges substantiallyparallel to the axis of shaft Ill which are preferably tapered asillustrated in FIG. I. These edges may be identified as lead and trailedges depending on the direction of rotation of the donor assembly. Aswill be seen hereinafter, this facilitates passage of the donor memberthrough the quantity of developer material 29 in the sump housing 112 asthe shaft 1% is driven to rotation by a suitable source of motive power.

The center of curvature of the donor members 26 and 23 is not coincidentwith the axis of shaft 13 as these members are mounted as shown in FIG.I. This feature is not critical although the curvature characteristic asillustrated is preferred since the rotation of donor members 26 and 2%will not tend to form a cavity in the material in the sump. In addition,by choosing a center of curvature different from the axis of shaft 1%,the donor members as they rotate about shaft ltl agitate and disturb thedeveloper material 29 in the sump more than if their center of curvaturecoincided with the axis of shaft 118. Furthermore, members 26 and 28need not have a surface curvature consistent with a single center ofcurvature.

The materials used may vary considerably. For example, components 20,22, 2d, 26 and 28 may be made of sheet metal with members 26 and 2t}optionally having their exterior or convex surface coated with asuitable insulating material to assist in triboelectrically attractingtoner particles from the sump as the donor assembly rotatestherethrough. The housing 12 may be either suitably formed metal,plastic, or any other suitable insulator.

Although the embodiment of FIG. l is not presented in the drawings froma point of view lying on a line perpendicular with the axis of shaft 18,such a view is easily visualized when it is considered that thecylindrical brush 2 and its associated structures are substantiallycoextensive with the area or zone on the recording medium in whichlatent patterns are to be recorded during the recording process.Accordingly, the donor assembly is preferably coextensive with the axialdimension of the brush 2. However, it may vary de pending upon theactual effective length of the developer mechanism. The door 14 may havea dimension perpendicular to the plane of the drawing substantiallyequal to the dimension of the donor assembly or may have a somewhatshorter dimension. Of course, the sump housing 12 has a dimensionparallel to the axis of shaft 18 slightly larger than the similardimension of the donor members 26 and 28. Support flanges 22 and 24 maybe substantially coextensive in this axial dimension with donor members26 and 28 or may have a dimension only sufficient to provide adequatesupport to the donor members. Flange member 24) as shown in FIG. 1 wouldoccupy a position on the far right side of the sump housing 12 as FIG. lis viewed from the right. The shaft i8 may extend through the sumphousing to be fixed to or even pass through a similar support flange asflange 20 at the left extreme of the donor housing. However, this isusually not necessary but may be provided for additional support of thedonor members 26 and 28. Members 22 and 26 and 24 and 28 may be attachedto each other in any suitable fashion such as rivoting, welding, etc.Also, while flanges 22 and 24 are described, donor members 26 and 28 maybe integral with flange 20.

in operation the donor assembly and more specifically shaft 18 is drivento rotate in the direction indicated by the arrow moving successivelydonor members 26 and 28 in a clockwise direction as FIG. 1 is viewedthrough the developer material 29 in the sump housing 12. Because of theunique construction of the donor assembly, this developer materialoccupies not only the low points outside of the donor members but alsooccupies a portion of the volume defined by these donor members. This ismade possible by the openings between the adjacent edges of the donormembers 26 and 28. These openings allow developer material to freelyenter and leave the volume defined by the donor assembly. Therefore, asthe donor assembly rotates, for example, and donor member 28 moves tocontact the fur brush 2, developer material within the donor assembly ispermitted through gravity to egress from the donor assembly via theopening between the trail edge of donor member 28 and the lead edge ofdonor member26 into the sump proper.

Similarly, as donor member 26 proceeds in a clockwise direction its leadedge directs developer material into the concavity formed by itsinterior surface and permits this developer material to flow back intothe sump as its trail edge passes the lowermost point of the the sump.This action of the donor members 26 and 28 thereby agitates completelythe material in the sump and permits developer material occupyingportions of the volume defined by the donor members 26 and 2b toreplenish the developer material in the sump itself. As is illustratedin FIG. l, the clearance between donor member 28 and the lowermostportion of the sump housing 12 is very small. In this way substantiallyall of the developer material in the sump is fully utilized by contactexposure to the moving donor members.

As the donor members 26 and 28 move through the developer material intosump l2 toner particles adhere themselves to the exterior convex surfaceof the donor members and are carried on these members into contact withthe bristles on brush 2. At this point, because of triboelectricattraction these toner particles are transferred and loaded onto thebristles of the developing brush 2. This brush which rotates in the samedirection at the point of contact with the donor assembly then conveysthese marking particles to the development zone defined by support 6where these marking particles are transferred to the recording medium '7to render visible latent patterns thereon.

Mounted on the housing 12 is a doctor blade assembly comprised of flangemembers 30 and 32 between which is supported a doctor blade member 34made of any suitable resilient material, such as silicon rubber orplastic. As shown in FIG. 1, these flange members 30 and 32 arerotatably fixed to a support shaft 36 to permit the doctor blade 34 tomove on the cam surface provided by donor members 26 and 28 as the donorassembly rotates in a clockwise direction. The function of the doctorblade is to meter a predetermined amount of toner adhering to theexterior surface of the donor members by removing excessive toner. Thisprevents non-uniform concentrations of toner being transferred to thefur brush 2 thereby creating variations in density of the developedelectrostatic charge patterns. Also coupled and fixed for rotation withthe doctor blade is a plurality of agitating fingers 3% which areuniformly spaced along the axis of support shaft 36 coextensive with theaxial dimension of the donor assembly itself. As shown in phantom inFIG. 1, as the doctor blade is moved up and toward the fur brush, thefingers 38 are also moved up an equal amount. As the trail edge of adonor member leaves contact with the doctor blade, the doctor blade willfall into the space between donor members causing the agitating fingers38 to also fall back against the interior surface of the sump housing12. This effectively agitates any developer material which may, undercertain environmental conditions, cake or build up on that side of thehousing 112 as a result of the clockwise movement of the donor assembly.

It will be realized because of the structure of the donor assembly thatdeveloper mixture placed in the sump via the opening closed off by thedoor 14 will fall under force of gravity into the donor assembly and onone side thereof. The openings between the lead and trail edges of thedonor members facilitates this loading. if these spaces were notavailable, a very limited amount of developer material could be added tothe developer sump without overflowing through the opening associatedwith door 14.

Therefore, in accordance with the principles of the present invention,developer material may be loaded into the sump readily without movingthe donor assembly itself. Furthermore, it can be seen that the type ofstructure of the donor assembly permits a maximization of the capacityof the sump for holding developer material and further acts to provide acam surface upon which agitating fingers can be actuated in a verysimple and inexpensive manner.

Reference will now be made to an alternative embodiment illustrated incross-section in FlG. 2. As shown, a shaft 46 which may be fixed forrotation in the same manner as shaft lltl of FIG. l is attached to asupport plate 42. of circular configuration. This plate supportsadjacent its periphery and parallel to its axis as well as the axis ofshaft 46) a plurality of donor members 44. As illustrated, these membersmay be cylindrical elongated rods which have dimensions parallel to theaxis of shaft similar to the dimensions of the donor members 26 and 28of FIG. l. The number of these rods may vary depending upon the speed ofrotation of the donor assembly as well as their own radius.

A doctor blade assembly 46 is illustrated as being attached to part ofthe shroud 48 isolating the fur brush 56 from the other parts of theapparatus in which this donor assembly is incorporated. Such an assemblymay take the form of that used in the embodiment in FIG. 11.

The shroud 48 may have associated with it two fixed snap ears 52 and 54on opposite edges which may accommodate and cooperate with two snapcatch grooves 56 and 58, respectively, molded on the inside surfaces ofa pliable, preferably plastic, sump housing 66. The ears 52 and 54 andgrooves 56 and have a dimension substantially equal to the dimension ofthe donor assembly of FIG. l in a direction parallel to the axis ofshaft 18.

The sump housing 66 of FlG. 2 is removable from shroud 48 by way of aformed handle or lever portion 62. By depressing this handle away fromthe shroud 48, the ear 54 is disengaged from the groove and the housing60 drops free of the shroud and the donor assembly.

Installation of the sump housing carrying a quantity of developermaterial 6ll is accomplished by simply pushing the housing 66) towardthe shroud 46 until the ears and grooves engage permitting the donorassembly to be immersed into the developer mixture in the sump housing.This housing may be shipped or stored with a removable paper orcardboard lid mounted inside the housing keeping the toner or developermaterial from spilling from the housing.

Not illustrated in FIG. 2, of course, are the side panels of the housing661 which are integral with the housing and formed of the same materialsuch as plastic or other pliable material.

The donor assembly in the embodiment of FIG. 2 operates in a manner verysimilar to that of the donor assembly illustrated in FlG. ll. As shaft4th is driven from a suitable source of motive power, the donor membersor elements move in a clockwise direction as illustrated by the arrowinto the sump of developer material thereby attracting to the surface ofeach of the donor members toner particles for conveyance to thedeveloping brush 56.

A pliable doctor blade assembly mounted on shroud 4% acts to contact thedonative surfaces of the donor members to meter a uniform layer of toneron this surface of each of the members 44.

The same novel features as set out in connection with the embodiment ofFIG. ll are also present in the embodiment of FIG. 2 in that the donormembers define a substantially cylindrical open volume in whichdeveloper material may be situated during operation of the donorassembly. In addition, as the donor assembly rotates it agitates andresituates the developer material in the sump to utilize completely thatmaterial. The clearance between the lowermost portion of the sumphousing 66 and the path defined by the movement of the donor members isvery close so that substantially all the developer mixture will reachthe donor members during the operation of the donor assembly.

It may be noted that the donor members or rods 44 need not necessarilybe of a circular cross-section and may be crescentic having theirconcave surface facing toward shaft 46 or may be simple solid membershaving semicircular cross-sections with the flat sides thereof facingthe shaft 40.

FIG. 3 illustrates another embodiment of the present invention whereindonor members 64 are driven through developer material 65 in a sumphousing 66 via two drive gears 68 and "I'll having about their peripherygear teeth 72. The donor members 64 may be circular cross-sectionedelongated rods as are illustrated in FIG. 2 coupled together by aflexible connecting or linking structure having links '74 between eachdonor member 64.

The links may be of any suitable material such as plastic segmentsmolded with rods or donor members 64, or even a single loop attached toeach member 64.

The drive gears 70 and 68 are driven by shafts in a direction indicatedby the arrows to bring donor members past a doctor blade assembly '76and into toner transfer relation with a developing brush 78. As shown,the pitch of the teeth 72 on the drive gears are such as to accommodatethe spacing between adjacent donor members 64 to provide a drivingsurface for the chain of donor members. Doctor blade type assembly '76is provided also adjacent wheel 70 to further isolate toner clouds fromother parts of the apparatus.

An additional bafile member may be provided intermediate the drive gears63 and '70 to prevent toner clouds or spillage from the sump toward thebrush 78 in case of disorientation of the donor assembly. The baffle 86may be supported from the sides of the sump housing 66 which are notillustrated in FIG. 3 or on the shafts 75 supporting wheels 68 and 70.

Each of the illustrated drive wheels 68 and 70 has a counterpart mountedon the same shaft and adjacent the other side of the sump housing tomaintain the donor members in parallel and to provide uniform drivingforce on the donor member chain.

The dimension of the donor members in the direction perpendicular to theplane of the drawing may be the same as the dimensions described for thedonor members in FIGS. l and 2.

In operation, drive wheel 68 acts to pull the donor members into thesump material 65 when the sump housing is at full capacity therebycausing toner adherence to the surface of the donor members 64. When thedeveloper material in the sump is gradually consumed, the larger segmentof the donor member chain lays upon and is drawn across the remainingdeveloper material. This continues until the chain of donor members isalmost contacting the bottom of the sump housing. The length of thischain is selected to accomplish this result taking into considerationthe spacing between drive wheels 63 and 70 as well as the size of thehousing 66.

As shown in FIG. 3, the chain of donor members 64 is placed initiallyabout drive wheels 68 and 70 to insure the requisite tautness in thearea of contact with the developing brush 7%.

As was the case with the donor members in the embodiment of FIG. 2,members 64 may take different configurations and still perform inaccordance with the principles of the present invention.

Reference will now be made to FIG. 4 which illustrates a donor assemblysimilar to a certain extent to the embodiment of FIG. 2 as well as FIG.ll wherein crescentic members 81 are positioned about a shaft 82 andfixed to rotate therewith by way of their coupling to or being integralwith flange member 84 which is attached to the shaft 82. The furthestouter extremity of each of the donor members 81 relative to the axis ofshaft 82 form a right cylinder by revolution when the assembly isrotated. The individual centers of curvature of the exterior surface ofthe donor members 81 do not coincide with the axis of shaft 82. Thisaugments the agitative effect of the donor members when they passthrough the sump of developer material. In fact the radius of curvatureof the exterior surfaces is greater than the radius of curvature ofinterior surfaces.

FIGS. 5 and 7 illustrate another embodiment of the present inventionincorporating some features not disclosed in earlier embodiments. FIG. 5is a cross-sectional view taken along lines 5-5 in FIG. 7 while FIG. 7represents a front view of the donor assembly with part of the housing,brush, and other portions broken away. In these FIGS. there isillustrated a sump housing 86 which defines a sump cavity or reservoiradapted to contain a quantity 85 (not shown in FIG. 7) of electroscopicmarking particles.

It is noted that the embodiments illustrated in FIGS. 5, 7, 8, 9, andare practical and efficient in using only toner in the sump without theusual addition of carry beads.

Mounted at the extremities of a shaft 08 for rotation therewith arelocated support discs 90 between which are tautly suspended a pluralityof very thin, flexible donor members 92. The shaft 88 is mounted forrotation on suitable bearing surfaces 94 in the side walls of thehousing 06 as shown best in FIG. 7. Also supported on shaft 88 are aplurality of thin baffle discs 96 which are held in spaced apartrelationship on the shaft and from the support discs 90 by spacersleeves 98.

Both the baffle discs and the sleeves are dimensioned to fit looselyupon shaft $8 in such a manner as to not readily rotate with this shaft.As a further impediment to the rotation of the baffle discs 96 with theshaft 88, a holding shaft 100 is used which passes through the portionof the baffle discs closest to the low portion of the sump housing 86.This shaft may be fixed permanently to the respective baffle discs ormay just be secured to one baffle to prevent its dislodging itself fromany of the extreme baffle discs.

The effect of holding shaft 100 is to weight the baffle discs so thatthey remain stationary while shaft 88 rotates. In addition, the toner inthe sump housing also affords greater resistance against this holdingshaft than against the thin baffle discs. This increased resistancefurther impedes rotation of these discs with shaft 88.

As best shown in FIG. 5, each baffle disc would normally have asubstantially circular configuration and conform as close as possible tothe interior surface of the sump housing 86. However, at that pointclosest to the developing applicator 102, shown as a fibrous member, thearea of a chord has been removed from the circle. This serves tomaintain a spacing between the baffle discs and the applicator 102 asthe latter rotates. Contact between the bafile discs and the brush orapplicator 102 is to be avoided since these baffle discs may attracttoner from the applicator 102 prior to delivery of this toner to thedevelopment zone or else add excessive toner to the applicator.

Only by way of example, certain dimensions have been used successfullyin this embodiment and are stated without any intention that thisembodiment be limited to these parameters. Depending upon the axialdimension of shaft 88 the baffles may be spaced approximately 0.75inches from each other and may be made of aluminum approximately 0.020inches in thickness so as to occupy as little space in the sump housingas possible.

The donor members 92 may be made of any suitable material eitherconductive or insulative. Conductive wires 0.006 inches in diameter havebeen successfully employed. The degree of tautness which these donormembers experience does not have to be great but only sufficient so asnot to sag or have slack at the time they contact the bristles of theapplicator 102.

As may be expected from the earlier description of the previousembodiments, as the support discs 90 rotate in the direction of thearrow shown in FIG. 5 they travel in a generally circular path through aquantity of toner confined in the sump housing 86 and attract and hold acertain quantity of this toner as they egress from the sump.

FIG. 6 illustrates what is believed to be the approximate toneraccumulation on any one of the donor members 92. The arrow in FIG. 6indicates the direction of movement of the donor member 92 both in thesump and outside the sump. As shown, a large quantity of toner builds upon the leading surface of the donor member while the remaining surfaceof this member retains a substantially uniform layer of toner. As notedhereinabove, the large amount of toner on the leading surface of thedonor member is undesirable and contributes to an inconsistent developedimage and it is therefore necessary to remove this excessive amount oftoner. In prior situations as well as in certain other embodiments ofthe present invention a doctor blade has served this function.

Because of the resilient characteristics of donor members 92 a doctorblade is not necessary for the removal of this excessive toner. Thisfunction can now be performed by a simple resilient member 104 which maycomprise a piece of metal wire, for example, 0.012 inches in diameter. Aloop may be formed in the wire as shown best in FIG. 5 to prevent anyfatiguing problems and one end of the wire may be mounted in housing 86by way of an appropriate mounting element 105. It should be understoodthat this element 104 may be made of other materials rather than metalsuch as rubber or plastic. The effect of this member 104 when itcontacts a donor member 92 as the support discs rotate is to slightlydeflect the donor member and then ll ll release it. This mechanicalaction may be compared to the picking of a guitar string. The results ofthis flicking of the donor member is to jar the excessive toner from thedonor member '92.

It is speculated that the success of this flicking action is due to thefact that the excessive toner is attracted to adjacent toner in theexcessive quantity on the donor member 92 to a lesser degree than auniform toner layer adhering directly to the surface of the donor member92. Consequently, the plucking action of the flicker member MM is suchas to dislodge all the toner carried by the donor member except for auniform layer held directly by the surface of the donor member itself.That toner which is flicked off is permitted to fall back into the sump.In this manner uniform amounts of toner are systematically andconsistently supplied to the attractive influence of the applicator i052through mutual contact therewith.

Because of the possibility of generating a large powder cloud of tonerat the region of contact between the flicker member R04 and the donormember 92, a protective hood R06 is mounted on housing as to extendtransverse to shaft 88 and coextensive with this region. This element isoptional and is used as an isolating feature between the donor assemblyand other portions of the apparatus in which the present invention maybe incorporated.

From the view afforded by FIG. 7' it may be appreciated that the bafflediscs create partial compartments along the axial dimension of the sumphousing as in which quantities of toner may reside until consumed duringthe operation of the donor assembly. This is particularly useful inmobile environments when the chance that the sump housing may bedisoriented from the horizontal is very great. if this occurs, such astilting the structure as illustrated in FIG. '7 30 with the horizontal(horizontal being from left to right as the FIG. is viewed) the tonerbetween baffle discs 96 will be shifted against an adjacent bafile discthereby preventing all or a large portion of the toner from shiftingfrom one side of the sump housing all the way to the other side. Becauseof the fine profile of the donor members 92 the clearance of thesemembers between the bottom of the sump housing 86 and the lower edge ofthe baffle discs as may be very small. This further makes possible theisolation of toner in adjacent compartments formed by the battle discssince the toner in such a small clearance will. form a block and notpermit more toner to pass beneath the baffle discs 6.

To further prevent large scale shifting of the toner from one extreme ofthe sump housing to the other and to assist the baffle discs, thehousing 86 may be pro vided with additional baffle plates I08 mountedthereon.

These baffle plates are seen on the left side of the shaft 88 in FIG.and seen best in FIG. '7 at that portion of the drawing wherein theapplicator I02 and some of the baffle discs 06 are broken away. From thelatter figure it may be noticed that these baffle plates 10% are locatedalong an interior side of the sump housing 86 in alignment with bafflediscs 9b mounted on shaft 88. Not seen in FIG. 7 but illustrated inFIIG. 5 are another set of baffle plates I00 which are located on theright side of shaft tit and mounted in a similar fashion as baffleplates I08 to the side of sump housing 86. These I12 baffle plates 1109are also in alignment with the baffle discs 96.

The combined effect of the baffle discs 96 and baffle plates 1103 and1109 is to divide the volume of the sump housing into individualcompartments to effectively prevent large scale shifting of toner in thesump housing when this housing is disoriented relative to thehorizontal.

Reference will now be made to FIG. 8 which illustrates alternativeapparatus for removing excess toner from the donor members 92. Elementsidentical with elements in FIGS. 5 and 7 are identified by the samereference numerals.

In place of the support discs there may be provided resilient supportarms 1110 which extend radially from a hub ll l2. fixed on shaft 88 torotate therewith. At the nonsupported end of each support arm there maybe a mounting arrangement for supporting one end of the thin donormember 92. A resilient member 114 is held in obstructing relationshipwith each of the support arms lllltll by the sides of the sump housing86. As the support arms move into contact with the flicking member 11Mthey are slightly deflected and then released having the same affect onthe excess toner on the donor member 92 as element l0l had in theembodiments of FIGS. 5 and 7.

In view of this disclosure it may be apparent that there may existalternative methods of vibrating the donor member 92 to achieve uniformtoner distribution on this member. For example, a small impact hammermay be timely actuated to gently tap each donor member 92 as it emergesfrom the sump of toner.

FIG. 9 represents an alternative method of allocating donor membersbetween support discs 90. In this figure a single piece of thin wire orother suitable material ll 16 is threaded back and forth between the twosupport discs 90 to form, as shown in FIG. 9, six taut segments oreffective donor members. Each one of the donor members l M forms anangle different than 90 with the plane of either support disc 90. It isapparent, of course, that single pieces of wire or material may be usedfor each length of donor member shown in FIG. 9.

An advantage of the structure of FIG. 9 is that the donor memberscontact the bristles or fibers of applicator T02 at the point of tonertransfer thereto at different angles each time there is contact. Thispromotes a fluffy and noncompacted applicator fiber which sometimesoccurs when a donor member such as a solid cylindrical device is used.Since the brush or applicator I02 does not become compacted or formed inone direction better development is possible. Furthermore, toner is notpermitted to build up on the side of the fiber remote from the donormember at point of contact but is dislocated from this position by thedifferent angle of impact on each succeeding donor member.

FIG. 10 illustrates another embodiment of the present invention which isvery similar to the view of the embodiment illustrated in FIG. 5 whereinsimilar elements are referenced by like numerals. The structureillustrated in FIG. 10, however, differs from that of FIG. 5 in theomission of flicking of vibrating member 104 and the addition of astriking element lid in the form of a thin flexible wire-like structure.This striking element may be a metallic wire, or other material, such asplastic, of approximately 0.012 inches in diameter and may be tautlysuspended between the sidewalls of the sump housing 86 clear of therotation of the support discs 9h.

The effect of the striking member is threefold. It serves totriboelectrically charge the fibers of applicator 102 so as to make itmore attractive to toner particles. In addition, its position within theeffective perimeter of the applicator which may be compacted afterdeveloping contact with a recording medium. And finally, but not of anyless importance, the striking element serves to redistribute excessiveconcentrations of toner throughout that portion of the applicator mostproximate to it.

It will be noted that the structure of FIG. 10 does not include vibratorelement MM as did the structure of FIG. 5. Therefore, as a result ofthis omission the donor elements 92 egress from the toner sump bearingamounts of toner as represented generally by the illustration of FIG. 6.This excessive amount of toner on the leading surface of the donorelement is undesirable if permitted to be transferred to the developingapplicator 102 without any other steps being taken to make this tonerconcentration more uniform. If nothing else is done, therefore, theseexcessive toner concentrations will be reflected in variations ofcontrast in the developed image on the recording medium. However, theaction of the striking element 118 is such as to dislocate thisexcessive toner clinging to fibers of the applicator to form a powdercloud of this excessive toner. This formation of a cloud of toner withinthe fibers of the applicator in conjunction with the triboelectriccharging of the fibers by striking element 118 cooperate to redistributethat toner which is in excess on certain fibers to fibers which canattract and hold more toner. This in effect takes excessive toner fromfibers holding too much toner and divides this amount of toner amongfibers which can hold more toner. As noted before, the toner being heldon toner is more weakly held by the fiber than toner contact the fiberitself.

The thin flexible nature of the striking wire or element 1 18 isbelieved to play an important role in the efficiency and effectivenessof the donor assembly and developing applicator. To replace the strikingwire 118 with, for example, a blade or planar member would not have thesame result as that achieved by a wire-like structure. For instance, astriking plate or blade, or other large area structure such as acomb-like member, will attract and build up excessive amounts of tonerresulting in poor operation of the developer applicator. In suchinstances, such structures may take toner unevenly from theapplicator,causing variation in the developed image. Furthermore, inother instances large amounts of accumulated toner may fall onto or bepicked up by the applicator to also cause variation in development or tobe dislocated from the applicator during its revolutions to contaminateother areas of the apparatus. The thin structure of the striking wire1118 is such that it will build up only a very small and predeterminedamount of toner and therefore will not accept any more build-up. Inaddition, the flexibility of the striking member 1 18 further insures noexcessive buildup as well as contributes further to the dislocation ofexcessive toner concentrations in the fibers of applicator 102; by itsvibratory action as the fibers and the striking member mutually deflectupon contact.

It should be noted that the embodiment of FIGS. 5,7, and 9, as well asFIG. 10, may very well operate without the flicking element 104 orstriking member 118, in the case of FIG. 10, if slight variations intoner concentrations in the applicator can be tolerated. This is madepossible by the flexible nature of the thin donor members 92 and 116.The contact of the applicators fibers with the donor member itself issufficient to vibrate the donor member thus dislocating excessiveamounts of toner therefrom. It is believed that while some of thedislocated toner is thrown into the applicator some falls back into thesump housing.

In summary therefore, objects of the present invention are achieved bythe movement of successive, discrete elongated donor members through asubstantially identical closed path which defines a dimension of avolume at least a portion of which is within a sump housing. Thishousing supports a quantity of marking particles, i.e., i.e., toner withor without carrier particles, within the defined volume.

The other dimension of the volume so defined is equal to the elongateddimension of the donor members. Since this volume is open as contrastedwith being solid or completely occupied with a solid integral member,marking particles may readily pass into and out of the volume.

The action of the donor members in transferring marking particles to thedeveloping applicator, such as the fur brush, is such as to supply suchparticles in a uniform manner to the applicator. This is possible inspite of the physical discontinuity of the donative surfaces of thedonor assembly. This is due to the relative velocities of the developingapplicator and the donor assembly. Preferrably, the relative velocityratio of the applicators surface and the surface of a single donormember at the point of mutual contact is approximately ten to one. Forexample, in the embodiment of FIG. 1, the donor assembly can be drivenat speeds from 4 to 40 revolutions per minute while the brush may rotatefrom 40 to 400 revolutions per minute. Therefore, the periphery of thebrush may make 1 complete revolution and receive marking particles froma single donor member.

These relative velocities are readily implemented by utilizing a singlesource of motive power and a conventional speed reducing geararrangement to couple the slower rotating shaft to the motor or motivepower source which could drive the faster shaft directly.

Donor members flexible enough to be vibrated or deflected with slightforce may be used without a doctor blade and in the presence of a puretoner sump. A wire-like striking member may also be used totriboelectrically charge and flufi the fibrous applicator as well asredistribute excessive amounts of toner in the applicator. Baffles inthe sump act to prevent or minimize large scale toner shifts normallyexpected when the donor assembly becomes disoriented with respect to thehorizontal.

While the present invention has been described with particularstructures in specific embodiments other modifications and equivalentsmay suggest themselves without departing from the inventive concepts ofthe present invention.

For instance, the doctor blade assembly of FIGS. 1 and 2 may easily besubstituted for the metering arrangement in the embodiment of FIG. 3 andvice versa.

Furthermore, the sump housing of MG. 2 may be used equally well with theother embodiments.

The donor assembly of the present invention may be used withelectroscopic marking particles as well as magnetic marking particles.

It may be apparent from this disclosure that any combination of thevarious donor members described hereinabove in connection with FIGS. lto 4 may be used effectively in a donor assembly. For example, one ofthe crescentic donor members of HG. ll may be superseded by one or moreof the rod-like donor member structures illustrated in FIG. 2. Any suchmodification or derivatives are within the scope of the presentinventron.

ln addition, donormembers having an oval or elliptical cross-section mayalso be employed in the embodiments of the present invention.

Although the present invention has been described in a system fordeveloping latent images deposited on a medium through electrography, itis itself not limited to any particular application. As may beappreciated, the present invention is also suitable in opticalxerographic and magnetic recording systems.

The number of donor members to be mounted on support discs 90 in theembodiment of l llGS. 5 to 110 may vary as a function of the desiredamount of toner to be supplied to the applicator 1102. This, as in theembodiments of lFlGS. l to 4, also depends on the relative rotationrates involved and the size of the applicator Striking element MS may beuseful when the number of wire-like donor members is very low. This isdue to the fact that if large numbers of donor members are used, theythemselves sufficiently fluff and charge the applicators fibers as thedonor assembly is rotated.

While the use of striking element llllt'l has been described inconnection with a particular donor assembly, it also has utility in anyfibrous applicator development system regardless of the donor assemblydesign.

The flicking or vibrating element has been described as being located atone side of the sump housing even though it may be located at the otherpoints along shaft Of course, more than one such element may also beemployed.

It should be understood that while the donor elements in the embodimentsdisclosed herein may be conductive they may also be conductive with aninsulative sleeve or layer coextensive with their exterior or tonerbearing surfaces.

Furthermore, while the embodiments of FIGS. 5 and 7 to it) have beendescribed using wire-like conductors or insulators having diameters of0.006 and 0.012 inches, elements having diameters around 0.003 inches toone thirty-second of an inch may also be used. The term wire-like isintended to include this range of diameters as well as other diametersas long as the element is flexible in the context of the presentinvention.

Therefore, while the invention has been described with reference to apreferred embodiment, it will be understood by those skilled in the artthat various changes may be made and equivalents may be substituted forelements thereof without departing from the true spirit and scope of theinvention.

What is claimed is:

lid

11. A developing system for latent patterns employing electroscopicmarking particles comprising:

a. a cylindrically shaped applicator adapted to be rotated about an axisand capable of holding electroscopic marking particles;

b. a plurality of elongated donor members each having a surface portioncapable of attracting electroscopic marking particles;

c. support means for supporting each of said donor members substantiallyin spaced parallel relation with each other;

(1. means coupled to said support means for moving said donor membersthrough a closed path, a portion of which brings said donor memberssuccessively into contact with said applicator.

2. A system as defined in claim ll wherein at least one of said donormembers are elongated rods having a substantially circularcross-section.

3. A developing system for latent images comprising:

a. an elongated housing containing a quantity of marking particles;

b. a plurality of planar baffle elements and movable means forsupporting them in said housing and spaced apart along the elongation ofsaid housing, said baffle elements extending into said quantity ofmarking particles held by said housing, said support means looselysupporting said baffle elements.

4. A developing system as defined in claim 3,

wherein:

a. said movable means comprises, a shaft mounted in said housing forrotation with respect thereto and passing through said baffle elementsand further including;

b. two support members mounted on the terminal portions of said shaftrespectively and fixed thereto for rotation with said shaft;

c. a plurality of thin, flexible wire-like donor members tautlysuspended in spaced apart relation between said support members;

d. an elongated fibrous applicator mounted for rotation about an axisand supported in substantially parallel relation with said shaft;

e. rotative power means coupled to said applicator and said shaft formoving said applicator and said donor members into mutual contact.

5. A developing system as defined in claim 4 further including means forvibrating said donor members prior to contact with said applicator.

6. A developing system as defined in claim 4 further including aflexible wire-like member suspended through said applicator and fixedindependent of said applicator and substantially parallel to said axis.

7. A developing system as defined in claim 4 further including aplurality of baffle plates mounted on the interior of said housing andeach being substantially in alignment with one of said baffle elements.

8. A developing system as defined in claim 4 wherein said housing has anarcuate interior portion and said baffle elements are discs having aperipheral portion proximate to and substantially uniformly spaced fromsaid interior portion of said housing.

9. A developing system as defined in claim 4 further including means forimpeding rotation of said baffle elements with said shaft.

10. A developing system as defined in claim wherein each of said supportmembers includes a hub portion mounted to said shaft and arm membersextending radially therefrom and wherein said vibrating means includes aflexible member mounted on said housing and extending into the paththrough which said arm members pass as said shaft is moved.

111. A developing system for latent images comprismg:

a. an elongated housing containing a quantity of marking particles;

b. a plurality of planar baffle elements supported in said housing andspaced apart along the elongation of said housing, said baffle elementsextending into said quantity of marking particles held by said housingand stopping short of said housing;

0. a shaft mounted in said housing for rotation with respect thereto andpassing through said baffle elements;

(1. two support members mounted on the terminal portions of said shaftrespectively and fixed thereto to rotation with said shaft;

e. at least one donor member suspended by said support members at adistance from said shaft such that upon rotation of said shaft said atleast one donor member passes between baffle elements and said housing;

f. an elongated fibrous applicator mounted for rotation about an axisand supported in substantially parallel relation with said shaft; and

g. rotative power means coupled to said applicator and said shaft formoving said applicator and said donor member into mutual contact.

12. A developing system according to claim 11 comprising a plurality ofthin, flexible wire-like donor members partly suspended in spaced apartrelation between said support members.

113. A developing system according to claim 11. including meanscooperating with one of said donor members for controlling the quantityof toner utilized by said applicator for developing said latent images.

114. A donor assembly comprising:

a. a plurality of elongated donor members each having a surface portioncapable of holding marking particles thereon;

b. support means for maintaining adjacent ones of said donor memberssubstantially in parallel and spaced apart;

0. means coupled to said support means for moving said donor membersthrough a path which defines a volume having one dimension substantiallyequal to the elongation of said donor members;

d. a housing containing a quantity of marking particles and supportedrelative to said support means to position a portion of said quantity ofmarking particles within said volume; and

e. a flexible elongated element having one end portion fixed and anotherend portion extending into said volume.

15. A donor assembly comprising:

a. a plurality of elongated flexible wire-like donor members each havinga surface portion capable of holding marking particles thereon;

b. support means for maintaining adjacent ones of said donor memberssubstantially in parallel and spaced apart- 0. means coupled to saidsupport means for moving said donor members through a path which definesa volume having one dimension substantially equal to the elongation ofsaid donor members;

d. a housing containing a quantity of marking particles and supportedrelative to said support means to position a portion of said quantity ofmarking particles within said volume; and

e. means for vibrating each of said wire-like elements.

16. A method of conveying electroscopic particles from a sump of saidparticles to a fibrous developing applicator comprising the steps of:

a. passing a thin flexible wire-like member through said sump ofelectroscopic marking particles; and,

b. contacting said thin flexible member with said applicator; and

c. vibrating said thin flexible member after it passes through said sumpand before it contacts the applicator.

1. A developing system for latent patterns employing electroscopicmarking particles comprising: a. a cylindrically shaped applicatoradapted to be rotated about an axis and capable of holding electroscopicmarking particles; b. a plurality of elongated donor members each havinga surface portion capable of attracting electroscopic marking particles;c. support means for supporting each of said donor members substantiallyin spaced parallel relation with each other; d. means coupled to saidsupport means for moving said donor members through a closed path, aportion of which brings said donor members successively into contactwith said applicator.
 2. A system as defined in claim 1 wherein at leastone of said donor members are elongated rods having a substantiallycircular cross-section.
 3. A developing system for latent imagescomprising: a. an elongated housing containing a quantity of markingparticles; b. a plurality of planar baffle elements and movable meansfor supporting them in said housing and spaced apart along theelongation of said housing, said baffle elements extending into saidquantity of marking particles held by said housing, said support meansloosely supporting said baffle elements.
 4. A developing system asdefined in claim 3, wherein: a. said movable means comprises, a shaftmounted in said housing for rotation with respect thereto and passingthrough said baffle elements and further including; b. two supportmembers mounted on the terminal portions of said shaft respectively andfixed thereto for rotation with said shaft; c. a plurality of thin,flexible wire-like donor members tautly suspended in spaced apartrelation between said support members; d. an elongated fibrousapplicator mounted for rotation about an axis and supported insubstantially parallel relation with said shaft; e. rotative power meanscoupled to said applicator and said shaft for moving said applicator andsaid donor members into mutual contact.
 5. A developing system asdefined in claim 4 further including means for vibrating said donormembers prior to contact with said applicator.
 6. A developing system asdefined in claim 4 further including a flexible wire-like membersuspended through said applicator and fixed independent of saidapplicator and substantially parallel to said axis.
 7. A developingsystem as defined in claim 4 further including a plurality of baffleplates mounted on the interior of said housing and each beingsubstantially in alignment with one of said baffle elements.
 8. Adeveloping system as defined in claim 4 wherein said housing has anarcuate interior portion and said baffle elements are discs having aperipheral portion proximate to and substantially uniformly spaced fromsaid interior portion of said housing.
 9. A developing system as definedin claim 4 further including means for impeding rotation of said baffleelements with said shaft.
 10. A developing system as defined in claim 5wherein each of said support members includes a hub portion mounted tosaid shaft and arm members extending radially therefrom and wherein saidvibrating means includes a flexible member mounted on said housing andextending into the path through which said arm members pass as saidshaft is moved.
 11. A developing system for latent images comprising: a.an elongated housing containing a quantity of marking particles; b. aplurality of planar baffle elements supported in said housing and spacedapart along the elongation of said housing, said baffle elementsextending into said quantity of marking particles held by said housingand stopping short of said housing; c. a shaft mounted in said housingfor rotation with respect thereto and passing through said baffleelements; d. two support members mounted on the terminal portions ofsaid shaft respectively and fixed thereto to rotation with said shaft;e. at least one donor member suspended by said support members at adistance from said shaft such that upon rotation of said shaft said atleast one donor member passes between baffle elements and said housing;f. an elongated fibrous applicator mounted for rotation about an axisand supported in substantially parallel relation with said shaft; and g.rotative power means coupled to said applicator and said shaft formoving said applIcator and said donor member into mutual contact.
 12. Adeveloping system according to claim 11 comprising a plurality of thin,flexible wire-like donor members partly suspended in spaced apartrelation between said support members.
 13. A developing system accordingto claim 11 including means cooperating with one of said donor membersfor controlling the quantity of toner utilized by said applicator fordeveloping said latent images.
 14. A donor assembly comprising: a. aplurality of elongated donor members each having a surface portioncapable of holding marking particles thereon; b. support means formaintaining adjacent ones of said donor members substantially inparallel and spaced apart; c. means coupled to said support means formoving said donor members through a path which defines a volume havingone dimension substantially equal to the elongation of said donormembers; d. a housing containing a quantity of marking particles andsupported relative to said support means to position a portion of saidquantity of marking particles within said volume; and e. a flexibleelongated element having one end portion fixed and another end portionextending into said volume.
 15. A donor assembly comprising: a. aplurality of elongated flexible wire-like donor members each having asurface portion capable of holding marking particles thereon; b. supportmeans for maintaining adjacent ones of said donor members substantiallyin parallel and spaced apart; c. means coupled to said support means formoving said donor members through a path which defines a volume havingone dimension substantially equal to the elongation of said donormembers; d. a housing containing a quantity of marking particles andsupported relative to said support means to position a portion of saidquantity of marking particles within said volume; and e. means forvibrating each of said wire-like elements.
 16. A method of conveyingelectroscopic particles from a sump of said particles to a fibrousdeveloping applicator comprising the steps of: a. passing a thinflexible wire-like member through said sump of electroscopic markingparticles; and, b. contacting said thin flexible member with saidapplicator; and c. vibrating said thin flexible member after it passesthrough said sump and before it contacts the applicator.